Ignition coils are already known which are intended to be mounted on a spark plug in order to supply electricity individually to such spark plug.
From the document EP-A-0 387 993, an assembly is known which is comprised of a spark plug firmly fixed to the secondary high-voltage part of an ignition coil. The primary low-voltage part of this coil is connected above the secondary part. This coil is thus partially fixed to the spark plug and is also intended for its individual supply of power.
However, such an assembly has two disadvantages. On the one hand, it is not unitary since it requires the mounting of the primary part of the coil after it has itself been mounted on the engine unit. And, moreover, it is incompatible with conventional spark plugs.
The present invention aims to overcome these difficulties.